Die for forming twist-drills.



No. 65!,356. Patented June l2, I900. J. 0. HOUSER.

DIE FOR FORMING TWIST DRILLS.

(Application filed Mar. 18, 1899.) N o M o d e I UNITED STATES PATENT ()FFICE.

JOHN O. HOUSER, OF PITTSBURG, PENNSYLVANIA.

DIE FOR FORMlNGTWlST-DRILLS.

SPECIFICATION formingpart of Letters Patent No. 651,356, dated June 12, 1900. Application filed March 18, 1899. Serial No. 709 570. (No model.)

T 00% whom it may concern:

Be it known that I, J OHN 0. HOUSER, a citizen of the United States, residing at .Pittsburg, in the county of Allegheny and State of Pennsylvania, have invented or discovered a new and useful Improvement in Dies for Forming Twist-Drills, of which the following is a full, clear, and exact description, reference "being had to the accompanying drawro ings, forming part of this specification, in

2o twist-drill sharpened at both ends.

My invention relates to the art of forming twist-drills by drawing a blank through forming-dies; and it consists in the improved die therefor. I

Referring now to the drawings, 2 is the die,

of hardened steel, provided with an opening 3,

through which the blank 4 is drawn by any suitable mechanism and in which it is formed. This opening is generally circular inform,

corresponding to the'diameter of the finished 4o sage by reason of the angular location of thedrill, and at opposite sides are the inwardlyextending groove-forming projections 5 5,'.an-' gularly arranged across the inner faces of the I opening 3, tapering from thepoint of contact with the blank inwardly, and terminating in curved finishing edges, so as to form in the blank the opposite spiral grooves 6 asthe blank is drawn through the die. Spiral movement will be imparted to the blank in its pas projections, and the gripping and'drawin'g mechanisms may be made to have a corresponding rotary movement when moving forwardly, or a rotating die may be used with a non-rotatin g blank with equally good results.

The die shown in Fig. 2 and, if desired,

any subsequent dies in the operation before.

finishing are designed'to accomplish but a partial reduction of the blank, while the finishing-die (shown in Fig. 4) is designed to enlarge the grooves to'the finished size and to reduce the intervening metal to a proper thickness.

' It will be understood that the continuouslyspiral finished blank may be made in any desired length, after which it may be cut into suitable sizes for work and then it is sharpened at each end to cutting-faces 7, when it is ready for use. g

. The advantage of a twist-drill having a continuous spiral, and'thus permittinga cuttingface to be provided at each end, will be appreciated, since such a drill may be used reversibly in the drill-chuck, allowing it to be used just twice as long as the ordinary drill without regrinding. The manufacture of such drills is rendered possible by my improved die, their cost is greatly reduced, the

uniformity of the drill is insured, and the density of the metal greatly increased, and these advantages contribute largely to the economical production of this class of drills as an article of manufacture and will be appreciated by those skilled in the art.

What I claim isl. Avdie for forming twist-drills from cylindrical blanks having an opening through which the blank is drawn, in which oppositely-disposed inner edges of the die conform to the diameter of the finished drill, and intermediate inwardly-extending projections conform to and produce the grooves oflthe drill "by compression in the passage of the 7 blank through the die.

, 2. A are for formingtwist-drills m t..-

idrical blanks provided with a circular openin g corresponding to the diameter of the blank and oppositely-disposed singularly-arranged groove-forming projections tapering from the point'of contact with the blankinwardly and terminating in curved finishing edges.-

In testimony whereof I have hereunto set my hand.

. JOHN'OrI -IO'USER.

Witnesses:

PETER J .EDWAnns, O. M. CLARKE. 

